1. Field of the Invention
The present invention relates to an enzyme-fixed bioreactor using an enzyme as a biocatalyst for carrying out a biochemical reaction on an industrial level.
2. Related Art Statement
Recently, research of bioreactors containing in a reaction column an enzyme-fixed catalyst carrying an enzyme fixed on the carrier surface, has been progressed rapidly. For that purpose, various carriers have been proposed, such as high molecular organic substances, for example, carrageenan, or polyacrylamide, etc., or usual ceramic substances, for example, alumina, zirconia, etc. However, in reaction systems using a bioreactor having an enzyme-fixed catalyst, operations at high temperatures are often necessary to prevent contaminations of the bioreactor caused by undesirable micro organisms, and bioreactors using organic substances as carriers of the enzyme-fixed catalyst have drawbacks in that they are deficient in chemical stability and heat resistant property to endure the operations at high temperatures. Meanwhile, bioreactors using usual ceramic substances as carries of the enzyme-fixed catalyst have drawbacks in that the catalyst can carry thereon only a small amount of enzyme, so that the productivity of the bioreactor using such catalyst is insufficient, and the whole plant has to be increased in size or the reaction time has to be prolonged.
For solving these drawbacks, bioreactors using porous glass beads as a carrier of the enzyme-fixed catalyst have been of interest (Sumio Sakka "Application of Ceramics to Enzyme-fixed Carriers" in "Kagakusohchi" [3], 1983, pp.52-58). The porous glass beads have many advantages of small pores having a diameter of a few hundred .ANG. by utilizing phase separation of glass resulting in a large specific surface area of 60-75 m.sup.2 /g, stable thermal and chemical properties, strong mechanical strength, and an outstanding capacity of enzyme that can be fixed on a unit amount of carrier as compared with conventional ceramic carriers. However, the porous glass beads have drawbacks in that they have to be produced by a complicated process of melting a glass at a high temperature of 1,500.degree. C., reheating the melted glass to 500-600.degree. C., and further heat treating the melted glass for a long time, so that they are very expensive as a carrier and difficult to use commercially in bioreactors of industrial scale. Thus, hitherto, a bioreactor having all of chemical and thermal stabilities, productivity, and economicity, has not been accomplished.